Well drilling bit



Fe'b. 28, 1933. .J. Hf HOWARD.

WELL DRILLING BIT .2.Sheets-Sheet 1 Filed June 14 1930 QA $2 mf v l'! al Feb. 28, 1933.

J. HY HOWARD WELL DRILLING BIT 2 Sheets-Sheet 2 Filed June, 14, 1930Patented Feb. 2 8, 1933 i 'UNITED STATES PATENT OFFICE 'JOHN H. HOWARD,or HUNTINGTON man, .CALIFORNIA AssIeNoa 'ro GLOBE OIL l'rooLs co, or LosNm'ros. caLIroaNIa,` a OOBPORLTION or CALIFORNIA WELL' naILLING BITApplication tiled June 14, 1980. Serial No. 461,203.

This invention re'lates to a well tool and relates more particularly toa well drilling bit.v It is a general object of the invention to providea simple, practical, and effective bit for use in the rotary method ofwell drilling.

An object of the invention is to provide a well bit embodyin rotatablecutters formed and mounted so t at they positively rotate relative tothe shank or body'of the tool to 'be particularly effective in drillingthe formation.

It is another object of the invention to rovide a bit in which cuttersare mounte on theshank to rotate about axes inclined relative to thelongitudinal axis of the shank and have cutting parts or bladesformed'to engage the walls of a well bore to destroy the formation andto cause positive rotation of the cutters.

It is another object of the invention to provide a well bit of thecharacter mentioned in which the cutting-parts or blades of the cuttersareV formed to engage the side wall of a well bore throughoutsubstantial portions of their lengths so that they are effective incausing rotation of the cutters to insure the etlcient operation of thetool and so that the wear is evenly distributed along the cutting ed esof the blades.

nother object of 'the invention is to provide a bit having cuttersmounted to rotaten on axes inclined ,relative to the longitudinal axisof the shank in which portions of, say the lower portions of, thelongitudinal or rea-ming cutting edges of the cutting blades arecurvedfto compensate for the inclination of the cuttersso that theyengage the formation throughout substantial portions of their lengths toevenly reamthe walls of-a well bore and to cause positive rotation ofthecutters.

It is a further object of the invention to provide a well drilling bitof the character mentioned above that is particularly effective indrilling a straight vertical hole or bore. The longitudinal or reamingcutting edges of the cutter blades by engaglng comparatively largeportions of the side wall of a well bore guide the bit to drill astraight bore.

Other objects and features of the invention will be best and more fullyunderstood from the following detailed description of a typical form andapplication of the invention throughout which description reference isha y to theaccompanying drawings, in which:

Fig..1 is a view illustrating the bit provided by the present inventionin operating position in a well bore. Fig. 2 is an enlarged sideelevation of the bit illustrating it in operatin w position in the-wellbore. Fig. 3 is a vertica .detailed sectional view taken as indicated byline 3 3 on Fig.v 2. Fig. 4 is an enlarged transversedetailed'lsectional view taken as indicated by line 4-4 on Fig. 3. Fig.5 is a 55 diagrammatic view illustrating the cutters within the wellbore, being a view taken at the upper ends of the cutters and lookingdown on the cutters. Fi 6 is a'diagrammatic 'view of the cutters in t ewell bore, being a 7o side elevation of the cutters, and Fig. 7 is a.`diagrammatic view illustrating the relative positions of the cutters andillustrating the manner of generating the roaming edges of 'the blades.

The construction of the shank or body l() may be varied somewhat,dependin upon the number of cutters provided on the it, the kind offormation in which the bit is to be opera-ted, etc. In the particularform of the so invention illustrated. in the 'drawings the body 10'isdesigned to carry two cutters 11 and includes a main shank portion 13and two enlargements 14 for mounting orcarryin the cutters 11. The shankportion 13 is pre erably of roundcross sectional configuration and isprovided at its upper end with an upwardly projecting taperedscrew-threaded pin 15. The pin 15 is provided to facilitate attachmentof the bit to an operating strin In the particular case illustrated inthe rawings the pin 15 is threaded into a socket 16 in the lower end ofa drill collar 17 carried at the lower end of an operating string 18.

The enlargements 14 project radially outward at the lower end of theshank portion 13. In the case illustrated where two cutters 11 aremounted on the body the enlargements 14 project outwardly atdiametrically opposite sides of the body. The enlargements 100 14 areinclined relative to a vertical plane passing through the longitudinalaxis of the body 10. The enlargements 14 are oppositely disposed oroppositely inclined and pre erably have their outer o r projecting sidesrounded as shown 1n the drawings. The body 10 is recessed at the upperends of the enlargements 14 to provide flat upper ends 19 on theenlargements. The upper ends 19 of the enlargements 14 are normal to theangles of inclination of the enlargements. The lower ends of theenlargements 14 are preferably flat and are parallel to the upper ends19 and at right angles to the longitudinal axes of the enlargements. Thebody 10 is provided with a central longitudinal circulation passage 20.`The passage 20 extends vertically through the body 10 from the upperend of the pin 15 to the lower end of the body 10. The lower portion ofthe passage 2() is restricted or of reduced diameter so that fluid isdischarged at high velocity from thelower end of the tool.

The cutters 11 are rotatably mounted at the lower ends of theenlargements 14. The cutters 11 are mounted to rotate about axesparallel with the longitudinal axes of the enlargements 14. The axes Rof rotation of the cutters 11 are oppositely inclined as will be readilyapparent from an inspection of Fig. 7 of the drawings. The cutters 11are rotatably mounted on straight shanks or stems 21 arranged throughaxial openings 22 in the enlargements 14. The openings 22 extendlongitudinally through theenlargements 14 and the stems 21 are arrangedin the openings 22 to project from the upper and lower ends of theenlargements. The portions 23 of the stems projecting from the lowerends of the enlargements 14 rotatably carry the cutters.

11 and are uniform in size and round in cross section. The4 openings 22are tapered upwardly and inwardly and the stems 21 are shaped to conformto the openings 22. The fit of the stems 21 in the openings 22 is suchthat the stems are prevented from moving upwardly in the openings. Nuts24 may be screwthreaded on the projecting upper ends of the stems 21 toprevent downward displacement of the stems. Locking keys or pins 25 maybe provided to lock the nuts 24 in position.

The axes of the stems 21 are in planes' angularly disposed relative tothe longitudinal axis of the shank or body 10 so that the cutters 11rotatably mounted on the lower projecting portions 23 of the stems arerotatable about axes lying in parallel planes parallel to the axis ofrotation of the body and the axes of rotation of' the cutters areinclined upwardly and outwardly in opposite directions relative to avertically disposed plane passing through the longitudinal axis of thebody 10. The cutters or cutter bodies 11 are provided with openings orsockets 26 receiving the portions 23 of the stems. The

cutters 11 may be retained on the stems 2,1 in any suitable manner. Inthe particular case illustrated the cutters 11 are retained on the stems21 by means of retaining members 25 arranged in registering annulargrooves 2'? in the sockets 26 and the axial portions 23 of the stems 21.The members 25a retain the cutters on the stems 21 so that they are freeto rotate and are held against longitudinal displacement. Thrust washers28 may be arranged on the stems 21 between the cutters 11 and thebottoms of the enlargements 14. In practice the thrusts, duringoperation, may be taken by the lower ends of the pins 21, and thewashers 28 may receive the thrusts upon wearing of the cutters and pins.The stems 21 may be held against rotation in the openings 22 by keys 29.

The cutting parts or cutting blades 12 are provided on the cutters orcutter bodies 11 to remove the formation and are such that they causerotationof the cutters 11 relative to the body 10 when the body isrotated. There is preferably a lurality of cutting blades 12 provided oneac cutter, the number and spacing of the blades depending upon the kindof formation ,in which the tool is intended to operate. In the preferredform of the invention there are two series or groups of cutting bladesprovided on each cutter 11. The cutters 11 are preferably provided witha plurality of main cutting and reaming blades 30 for engaging thebottom and side walls of the well bore B, and reaming blades 31 forengaging the side walls of the bore B. The blades 30 and 31 projecttangentially from the cutter bodies 11 and extend longitudinally oraxially of the cutter bodies. In the particular form of the inventionillustrated in the drawings, the blades 30 and 31 are substantiallytangential to concentric circles having diameters approximately onefourth as great as the diameters of the cutter bodies.

The main cutting blades 30 are equally spaced about the central axes ofthe cutters and the reaming blades 31 may be arranged between the mainblades 30. The main cutting blades 30 project outward from the cutterbodies 11 and extend longitudinally of the cutters from the upper endsof the cutters to points below the lower ends of the cutters. The blades3() may be of substantially uniform thickness throughout their lengths.The main cutting blades 30 project downwardly from the cutter bodies 11to engage the formation at the bottom of the well bore B and areprovided with cutting edges 32 at their lower ends to remove theformation at the bottom of the bore. The cutting edges 32 are pitched toeffectively shear the formation at the bottom of the well bore. edges ofthe downwardly projecting portions of the cutting blades 30 may becurved upwardly and inwardly from the cutting edges 32 to the bottoms ofthe cutter bodies 11. The

The inner `cut to full size. p 6 represent the paths of the upper endsof the cutting blades 30 are of the same size and are positioned andrelated so that the entire bottom of the well bore is engaged or actedupon by the cutting edges 32 during a cornplete revolution of the toolwith the exception of asmall central core which is destroyed by theiiuid discharging through the passage 20. The lower cutting edges 32 ofthe blades may be comparatively straight and are inclined relative tothe axes of rotation of the cutters to effectively act upon the bottomof the well bore.

The reaming or side cutting edges of the blades 30 and 3l are designedto act upon the side walls of the well bore B to cut the bore to fullsize and to positively cause rotatlon of the cutters to ensure theeffective operation of the tool. The shape ofthe longitudinal or reamingedges of the cuttingblades 30 and 31 is a feature of the invention andprovides a particularly eiective well .drilling tool. In accordance withthe preferred form of the invention, the lower portions 33of the long1.tudinal or reaming edges 33 of the blades 30 are curved and thecurvature or shape of the lower edges 33 is such that they activelyengage the walls of the well bore throughout their lengths. Due to theinclination of the axes of rotation of the cutters from the vertical,the edges 33 successivel engage the walls of the well bore. Inaccordsiince with the preferred form of the invention, the lowerportions 33Cl of the edges 33 of the blades arel curved longitudinallyabout a point adjacent the intersection of planes including the axes ofrotation of the cutters and the central axis of the well bore B. Inother words, the general curvature of a cutting edge 33a is determinedby describing an arc in a horizontal plane about an axis adjacent thepoint of intersection of a plane including an axis R of a cutter 11 andthe bore axis A and then projecting the arc downward along the lowerportion of the blade 30 which'is pitched at 15o from the vertical. Itwill be obvious that the inclination of the cutters from the verticalwill determine the curvature of the cutting edges 33 of the cuttingblades. v

In practice it has been found desirable to pitch the cutters 11 torotate about axes approximately 150 from the vertical axis of the wellbore B. Fig. 5 of the drawings is a diagrammatic view taken on ahorizontal plane normal to the axis A of the well bore B intersectingthe axes of rotation R of the cutters at the upper ends ofthe cutters.The circle B represents the walls of the well boro at the upper yends ofthe cutters where it is The curves X in Figs. 5 and cutting blades,relative to the body of the tool only, and the curves Y represent thepaths of the lower edges of the blades 30 with respect to the shank orbody of the tool, if designed to cut to the same diameter as the upperends. upper and lower edges of the blades during operation of the toolare aproximately hypotrochoids.

In practice the lower edges are made to cut to a-diameter slightly lessthan that cut by theV upper ends, for instance, they are made to cut toa diameter represented by the circle B. When formed in this manner thelower ends of the edges 33 describe the circles Y. The upperV portionsof the longitudinal or reaming cutting edges 33 of the cutters may bestraight and the lower portions 33a extend gradually between thestraight upper portions and the lower edges of the blades as shown inFigs. 5 and 6 and engage the walls of the well bore B throughout theirlengths. The side edges 33 connect the curves X and Y- and the curvedportions 33a have centers adjacent the point D of intersection of theplane intersecting the axes of rotation R of the cutters at the upperends of the cutters and the axes A of the well bore. In practice thecenters of curvature of the cutting edges 33a may be moved out from thepoint of intersection D toward the respective cutters 30 so that thecurvatures of the edges 33a will have shorter radiuses. For example, thecenters of curvature of the cutting edges may be at the points D so thatthe blades have cutting edges 33 shown in broken lines connecting thecircles X and Y. By forming the cutting blades with edges 33 curvedabout points D outwardly of the point of intersection D, the blades areparticularly effective as the edges 33a cut into the formation andeii'ectively'destroy the formation at the sides of the well bore B uponthe rotation of the tool. Further, if desired, the angle W ofinclination of the cutters from the vertical axis Aof the Well bore maybe increased or decreased so that the point of intersection D of thehorizontal plane passing through the points of intersection of the axesof the cutters and the upper ends of the cutters will be movedvertically .along the axis A of the bore giving the cutters either agreater or smaller cutting diameter at theirlower edges Y. It has beenfound practical, however, to pitch the cutters 11 at substantially 15from the vertical and to curve the-edges 33a about points slightlyoutward ofthe point of inter-- section D, for example, about the pointsD so that the lower ends of the edges 33 cut the bore to the line B. Bycurving the edges 33a in this manner, they act upon the walls of thewell bore in an effective manner and positively` cause rotation of thecutters 11.

The upper or reaming cutters 31 have cutting edges 34 of the sameconfiguration as the upper portions of the edges 330i the'blades 30 toaid in reaming or destroying the formation at the upper portions of theblades 30. A blade 31 may be provided between each main blade 30 asillustrated in the drawings. The

The paths of movement of the reaming blades 31 may extend longitudinallyof the cutter bodies between their upper and lower ends.

It is believed that the operation of the bit provided by the presentinvention will be readily apparent from the foregoing detaileddescription. The invention provides a bit wherein the cutting action ofthe cutting blades 30 and 31 is distributed throughout the lengths ofthe blades so that the wear on the blades is evenly distributed. Bycurving the lower portions 33* of the edges 33 of the cutting blades sothat they engage the formation of the well bore throughout theirlengths, the bit operates to cut the bore to size for a substantialperiod, as the blades will remain to size until worn throughout theirlength. The edges 33 being formed or sha to effectively engage the sidewalls of the bore B, cause the cutters 30 to be rotated so that they areeffective in cutting the formation and so that the cutters will nottrack in the formation. Further, the edges 33 and 34, being shaped inthe manner described, are particularly effective in guiding the bit todrllla straight vertical hole. The circulation fluid discharges from thepassage 2O between the cutters l1 the cutters and to flush the blades 30and 3l of the cutters. v

Having described only a typical preferred form of my invention, I do notwish to limit myself to the specific details set forth, but wish toreserve to myself any changes or variations that may ap ear to thoseskilled in the art or fall within the scope of the following claims:

Having described my invention, I claim:

1. A well bit including, a body to rotate about a vertical axis, acutter mounted at the lower end of the body to rotate about an axis in aplane inclined downwardly and outwardly relative to the vertical axis ofthe body, and cutting parts on the cutter having cutting edges to engagethe formation at the bottom of a well bore to make a substantially flatbottom wall in the bore, and having substantially parallellongitudinally curved side edges curved downwardly and inwardly withrespect to the axis of rotation of the cutter to engage the formation atthe side of the well bore through substantial portions of their lengthsto form a round bore.

2. A well bit including, aV body, a cutter mounted at the lower end ofthe body to rotate about an axis in a plane inclined relative to thevertical axis of the body, and a plurality of circumferentially spacedlongitudinal cutting blades on the cutter having lower'cutting edges toengage the formation at the bottom of a well bore to make asubstantially flat bottom wall in the bore, and substantially parallellongitudinal side edges curved downwardly and inwardly with respect tothe axis of rotation of the cutter to engage the side to destroy thesmall core left by` wall of the well bore throughout substantialportions of their lengths to cut a round bore.

3. A well bit including, a body, a cutter mounted at the lower end ofthe body to rotate about an axis in a plane inclined relative to thevertical axis of the body, and a p`.urality of circumferentially spacedcutting blades on the cutter, the spacings of the several blades beingsubstantially uniform throughout the lengths of the blades, the bladeshaving lower cutting edges to engage the formation at the bottom of awell bore, to cut a substantially flat bottom wall in the bore, andlongitudinally curved side edges curved downwardly and inwardly withrespect to the axis of rotation of the cutter to engage the side wall ofthe well bore throughped out their lengths to cut a` round bore.

4. A well bit including, a body to rotate about a vertical axis, cuttersmounted at the lower end of the body at opposite sides of the verticalaxis of the body to rotate about axes in planes inclined relative to thevertical axis of the body and in opposed angularity relative to eachother, and spaced cutting parts on the cutters, the spacings of thecutting parts being uniform throughout the lengths of the cutting parts,the cutting arts having lower cutting edges to engage tiie formation atthe bottom of a well bore to cut a substantially flat horizontal bottomwall, and longitudinally curved side edges curved inwardly anddownwardly relative to the axes of rotation of the cutters to engage thewall of the bore throughout substantial portions of their lengths to cuta round bore.

5. A well bit including, a body, cutters mounted at the lower end of thebody at opposite sides of the vertical axis of the body to rotate aboutaxes in planes inclined relative to the vertical axis of the body and inopposed angularity relative to each other. and cutting parts on thecutters having lower cutting edges to act on the formation at the bottomof a well bore, and snide cutting edges extending longitudinally of thecutters and being longitudinally 'curved inwardly and downwardlyrelative to the axes of rotation vof the cutters to a't on the formationat the side wall of the bore to cut a round bore and cause rotation ofthe cutters, the cutters having diameters less than one half thediameter of the bore.

6.4 A well bit including, a body, cutters suspended at the lower end ofthe body at opposite sides of its axis to rotate about axes in planesinclined relative to the vertical axis of the body and in opposedangularity to each other, and spaced cuttin g blades on the cuttershaving lower cutting edges to act upon the formation at the bottom of awell bore to cut a substantially horizontal bottom wall, andlongitudinal side cutting edges rurved inwardly and downwardly fromtheir upper ends to act upon the formation at the wall of the well bore,the spacing of the adjacent cutnal axis concentric mounted at the lowerend ting blades being Vuniform throughout the lengths of the blades.

7. A well bit including, a body, a cutter suspended at the lower end ofthe body to rotate about an axis in a plane inclined relative to thevertical axis of the body, and spaced cutting blades on the cutterhaying transverse lower cutting edges to act upon the formation at thebottom of a well bore, and longitudinal side edges with substantiallyaxial upper portions and lower portions curved about a pointsubstantially coincident with the point of intersection of a plane n-.,

cluding the axis of rotation of the cutter and the axis of rotation ofthe body, the spacing of the adjacent cutting blades being uniformthroughout the lengths of the blades.

8. A well bit including, a. body, a cutter mounted at the lower end ofthe body to rotate about an axis in a plane inclined relative to theaxis of rotation of the body, and spaced longitudinal cutting parts onthe cutter extending throughout the length of the cutter and havinglower cutting edges to cut a substantially flat bore bottom and havingside cutting edges with their lower portions curved about a pointadjacent the point of intersection of said plane and the axis ofrotation of the body, the spacing of the cutting parts beingsubstantially equal throughoutv the lengths of the cutting parts.

9. A well. bit including,

a body, a cutter of the cutting parts of a cutter b'eing curved about apoint substantially coincident with the point of intersection of aplane'including the axis of rotation of the said cutter and thelongitudinal axis of the body, the cutters having maximum diameters lessthan onefhalf the diameter of the well bore. In witness that I claim theforegoing I have hereunto subscribed my name thisr24th day of May, 1930.-y

JOHN H. HOWARD.

mounted at the lower endv of the body to ro` Y tate about an axis in aplane inclined relative to the axis of rotation of cumferentially spacedlongitudinal `cutting parts on the cutter, the spacing of the cuttingparts being uniform throughout the lengths of the cutting parts, thecutting parts having side cutting y about a point adjacent the point ofintersection of said plane and the axis of rotation of the body toengage the formation at the wall of a well bore for substantial portionsof their lengths to cut a round bore and having substantially transverselower cutting edges to engage the well bore to cut a substantially fiathorizontal bottom wall.

10. A well bit including, a body, a cutter of the body to rotate aboutan axis in a plane inclined relative to the axis of rotation of thebody, and circumferentially spaced longitudinal cutting parts on thecutter having cutting edges curved about a point radially outward of thepoint of intersection of said plane and the axis of rotation of thebody, the spacing of the cutting parts being substantially equalthroughout the lengths ofthe cutting parts.

11. A well tool for use on a drilling string including a body having acentral longitudiwith the axis of rotation of the drilling string,cutters mounted at the lower end of the body at opposite sides of itsthe body, and cir= edges curved longitudinallyformation at the bottom ofthe

